"Zero progress has been made in what is specifically aimed at kids," said Davis, a 1988 Oscar winner for her supporting role in "The Accidental Tourist."

"What children see affects their attitudes toward male and female roles in society," she said. "And, as they watch the same shows and movies repeatedly, negative stereotypes are imprinted over and over again."

The study (PDF) looked at 122 top-grossing domestic family films rated G, PG or PG-13 from 2006-09. Of the 5,554 speaking characters studied, 71 percent were male and 29 percent female. That's a ratio of 2.42 males to every female, which has not changed significantly in 20 years, according to the study.

Some of the films in the study included "WALL-E," "Ocean's Thirteen," "Ratatouille," "Pursuit of Happyness," and "Confessions of a Shopaholic." The full list is posted in the study's appendix.

Often female characters are portrayed in "sexualized attire" and as physically attractive, the study found.

"Eye candy is not for kids," said Davis, who said lopsided gender roles tend to reinforce stereotypes.

"We just want diverse female characters and more of them," she said. "We know that if girls watch female characters in unstereotyped activities, it heightens the possibility that girls will seek employment in nontraditional vocations."

The mother of three, a best actress Oscar nominee for "Thelma & Louise," more recently played a U.S. president in the 2005-06 television drama "Commander in Chief."